Mercury switch



Sept. 20, 1932. T. A. BOTH MERCURY SWITCH Filed Dec. 10. 1931 INVENTOR TONJES A. BOTH 6 12': 4-220 raga to the plane of the strap.

i Patented Sept. 20, 193 2 UNITED STATES PATENT OFFICE TONJES A. BOTH, OF STRATFORD, CONNECTICUT, ASSIGNOR TO'THE BRYANT ELECTRIC COMPANY, OF BRIDGEPORT, CONNECTICUT, A CORPORATION OF CONNECTICUT MERCURY SWITCH.

Application filed. December 10, 1931.

This invention relates to lever operated switches. More particularly it relates to a lever operated switch in which an electric circuit is made or broken by the movement of a body of mercury.

It is an object of my invention to provide a lever operated switch which is quieter in operation than the lever operated switches hereinbefore known.

Another object is to simplify the construction of lever operated mercury switches.

Other objects and advantages of my invention will appear as it is described in connection with the accompanying drawing.

In the drawing Figure 1 is a side elevation view partly in section of a switch constructed according to the principles of my invention.

Figure 2 is an elevation section view, taken on a central plane through the switch shown in Figure 1.

Figure 3 is a plan view of the switch shown in Figure 1.

Figure 4 is a section 4-4 of Figure 3.

Figure 5 is a plan view of the switch base.

Referring to the drawing, the switch comprises a recessed switch base 10 having a hollow, oval, rearwardly-projecting portion 12 forming a well 1 1 for a movable mercury tube 16 hereinaiter described. The switch base 10 is supported by a supporting strap 18 which view taken on the line has a rectangular aperture in-its central portion through which projects the hand lever 20 of a switch actuating member 21. Adjacent'each end and slightly to one side of the center line, the switch base with a recess 22 for the accommodation of two fingers 24 formed upon one side of the supporting strap 18 intermediate its ends and bent inwardly of the switch at right'angles These fingers 24; are formed only on one side of the strap and no accommodating recesses for them are formed in-the base on the opposite side of the center line. Therefore-the strap can only be assembled upon the switch base in one position. This is an important feature of the invention, since most mercury switches must be placed in a given position in order to be when the switch is moved 10 is provided Serial No. 580,164.

successfully operated. The switch supporting strap may be provided with a legend such as the word top upon its upper portion to aid in properly installing the switch. The switch actuator 21 is mounted for tilting movement on the switch base 10 by providing the base at each side of the mouth of the well 11 with a V shaped bearing surface or depression 30 and providing the switch actuator 21 with a pair of V shaped pivots 32 which are of less angular extent than the depressions 30 and are adapted to seat in the depressions 30.

Above the switch actuator 21 is a spring 38 of resilient sheet metal which is provided with a central aperture 40 corresponding to the aperture in the supporting strap for accommodation of the hand lever 20. An extension 42 of the spring lies under the end portion of supporting strap 18 between it and the base 10. at the bottom of the switch. This extension 42 is provided with an aperture for the reception of the lower screw 44 by which the supporting strap 18 is held upon the switch base. The spring 38 is provided with a pair of spaced indentations 46 on each side thereoi to accommodate two rollers 36 when the switch is in off and on position. The-resilience of-the spring is suffi cient to impart a slight snapping movement from on to otli position and vice versa. In addition to its snapping function the spring also acts as a noiseless resilient stop to arrest the normal movement of the actuator between on and cit positions. -The rollers 36 are formed of a central disc portion and two opposed axial extensions forming the spindle of the roller. The rollers are loosely seated in cavities 34 located one on each side of the hand lever .20 in the outer surface of the member 21. The cavities are similar in shape and slightly larger than one half the rollers, so that the rollers may be readily rotated therein. The use of the rollers is desirable because it tends to eliminate friction between the switch actuator and s ring and thus makes for longer life of te switch. The rollers are held in the cavities 34: only by the spring 38 which is in turn held by the supcated on one side of the switch vice versa to make or break an electrical connection between the two fixed contacts in the tube. This tube forms no part of my invention and therefore need not here be described in further detail. It will suflice to say that anyone of a number of well known tubes could be adapted for use in connection with my switch mechanism.

The glass tube 16 is held to the switch actuator by means of a cradle 50 which is stamped from sheet metal and attached, by screws or otherwise, to the actuator 21 and has arms 52 which embrace the tube. The fixed contacts of the tube are connected b flexible leads 54 to wire terminals 56, 56 lobase at opposite ends thereof whereby the switch may be connected in an electric circuit- Since the cradle 50 may, in most cases, be made of metal, and the leads 54; may be uninsulated it is desirable to keepthe leads out of the switch well .14 so as to avoid their contacting with the cradle. I accomplish this by providing a pair of channels 57, 57 extending transversely of the switch base on opposite sides of the switch well, one (57)- leading from one of the wire terminals 56 and the in the switch base, thus sim other 57) from the other terminal 56'. The slack of the leads is taken up by 100 ing them around in the channels 57, 5 construction it is possible to assemble the wire terminals with the leads and the movable parts of the switch and'lay them all as a unit sembly-of the device as we the leads.-

In operation as the hand lever 20 is tilted from the position shown in full lines in Figures 1 and 2, to the position shown in'dotted l as protecting lines in Figure 2, the switch will be moved from on to off position and as it is again moved back to the full line position it will again close the circuit.

" It is worthy of mention that the V shaped pivot for the switch actuator is especially ad- ..Vant'ageous in this type of switch because it prevents overthrow of the. actuator by reason of'the. sides of the V shapedpivots32 of the actuator engaging with the sidesof-the be'ar-..

ings or depressions 30, thus preventing the glass tube from being pressed against-the (not shown) fixedly mounted there-' ith thislifying the aswall of the well 14 in case of an attempt to push theswitch beyond the normal on or off position as defined by a leaf spring.

Many changes and modifications of my invention will occur to those skilled. in the art, therefore I do not limit myself to the specific form of the parts as shown.

claim I 1. A mercury switch comprising an insulating base having a pair of V-shaped bear ings therein, a tiltable switch actuator having V-shaped ivots fitting in said bearings and havin a ever portion extending therefrom where y said actuator may be manually moved, 'a cradle secured to said actuator, a receptacle held in said cradle and containmg a body of mercury and a plurality of contacts for making and breaking an electri circuit.

2. A switch comprisin an insulating base a switch actuator pivota 1y mounted in sai base and having a lever portion extending therefrom for manually actuating the switch, H a leaf spring secured above said actuator;

rollers loosely mounted in cavities in said actuator and held therein by said spring, said spring having a plurality of indentations for y said roller to hold said actuator in on and off positions in combination with circuit making and breaking means carried by said actuator.

3. A switch comprising an insulating base, a switch actuator pivotally mounted in said base and having a lever portion extending therefrom for manually actuating the switch, a leaf spring secured above said actuator, rollers loosely mounted in cavities in said actuator and held therein by said spring, said spring having a plurality of indentations for said roller to hold said actuator in on and off positions, in combination with a receptacle mounted on said actuator and provided with a pair of contacts and containing a. body of mercury which is adapted to make and break electrical connection between said contacts. r

' 4. A mercury switch comprisingafi insulating base, a switch actuator pivotally mounted on said base and having a lever portion extending therefrom for manually ity of indentations for said roller to hold the switch in on and off positions, and circult making and breaking means including a'body of mercury mounted'iip'on said actuator.

5. A mercury 7 switch comprising an insul 'tingbase-having a pair of V -shaped bearings therein, a tiltable switch actuatorhaving V-shaped pivots fitting in said bearings 'tion to manually move said actuator,

and having a lever portion extending therefrom whereby said actuator may be manually moved, a cradle secured to said actuator, a receptacle held in said cradle and containing a body of mercury and a plurality of'contacts for making and breaking an electric circuit, a spring above said actuator, rollers loosely mounted'in cavities in said actuator and engaging said spring, said spring having indentations for said rollers, and a supporting strap for said base serving to hold all said parts in assembled position.

6. In a mercury switch, a recessed insulating base, mercury circuit making and breaking means contained therein, a basesupporting strap having a legend thereon, said strap being provided with means permitting its assembly upon said base in one position only.

7. A mercury switch comprising an insulating base, switch actuator bearings and lead wire channels molded therein, a manually operated switch actuator pivoting in said bearings, a mercury container mounted on said actuator having a plurality of fixed contacts connected to said container lead wire terminals mounted on said base, flexible lead wires, said flexible lead wire connecting the fixed contacts and wire terminals and seated in said channels.

8. A switch comprising an insulating base, lead wire channels extending transversely in said base, a manually operated switch actuator, circuit making and breaking means carried by said actuator, flexible lead wires connected to said means, wire terminals mounted on the base, said flexible lead wires being connected to said terminals and being seated in said channels.

9. A mercury lating base having molded bearings therein,

a molded switch actuator having integral pivots pivoting in said bearings, a lever pora cradle secured thereto, in combination with mercur circuit making and breaking means carrie by said actuator.

In testimony whereof I have signed my name to this specification.

. TONJES A. BOTH.

switch comprising an insu- 

